<?php  // $Id: rsslib.php,v 1.52.2.4 2008/09/16 08:55:43 moodler Exp $
	   // This file contains all the common stuff to be used in RSS System

//This function returns the icon (from theme) with the link to rss/file.php
function rss_get_link($courseid, $userid, $modulename, $id, $tooltiptext='') {

	global $CFG, $USER;

	static $pixpath = '';
	static $rsspath = '';

	//In site course, if no logged (userid), use admin->id. Bug 2048.
	if ($courseid == SITEID and empty($userid)) {
		$admin = get_admin();
		$userid = $admin->id;
	}

	$rsspath = rss_get_url($courseid, $userid, $modulename, $id);
	$rsspix = $CFG->pixpath .'/i/rss.gif';

	return '<a href="'. $rsspath .'"><img src="'. $rsspix .'" title="'. strip_tags($tooltiptext) .'" alt="'.get_string('rss').'" /></a>';

}

//This function returns the URL for the RSS XML file.
function rss_get_url($courseid, $userid, $modulename, $id) {
	global $CFG;
	require_once($CFG->libdir.'/filelib.php');
	return get_file_url($courseid.'/'.$userid.'/'.$modulename.'/'.$id.'/rss.xml', null, 'rssfile');
}

//This function prints the icon (from theme) with the link to rss/file.php
function rss_print_link($courseid, $userid, $modulename, $id, $tooltiptext='') {

	print rss_get_link($courseid, $userid, $modulename, $id, $tooltiptext);

}
//This function iterates over each module in the server to see if
//it supports generating rss feeds, searching for a MODULENAME_rss_feeds()
//function and invoking it foreach activity as necessary
function cron_rss_feeds () {

	global $CFG;

	$status = true;

	mtrace('	Generating rssfeeds...');

	//Check for required functions...
	if(!function_exists('utf8_encode')) {
		mtrace('		ERROR: You need to add XML support to your PHP installation!');
		return true;
	}

	if ($allmods = get_records('modules') ) {
		foreach ($allmods as $mod) {
			mtrace('		'.$mod->name.': ', '');
			$modname = $mod->name;
			$modfile = "$CFG->dirroot/mod/$modname/rsslib.php";
			//If file exists and we have selected to restore that type of module
			if (file_exists($modfile)) {
				include_once($modfile);
				$generaterssfeeds = $modname.'_rss_feeds';
				if (function_exists($generaterssfeeds)) {
					if ($status) {
						mtrace('generating ', '');;
						$status = $generaterssfeeds();
						if (!empty($status)) {
							mtrace('...OK');
						} else {
							mtrace('...FAILED');
						}
					} else {
						mtrace('...SKIPPED (failed above)');
					}
				} else {
					mtrace('...NOT SUPPORTED (function)');
				}
			} else {
				mtrace('...NOT SUPPORTED (file)');
			}
		}
	}
	mtrace('	Ending  rssfeeds...', '');
	if (!empty($status)) {
		mtrace('...OK');
	} else {
		mtrace('...FAILED');
	}

	return $status;
}

//This function saves to file the rss feed specified in the parameters
function rss_save_file ($modname, $mod, $result) {

	global $CFG;

	$status = true;

	if (! $basedir = make_upload_directory ('rss/'. $modname)) {
		//Cannot be created, so error
		$status = false;
	}

	if ($status) {
		$file = rss_file_name($modname, $mod);
		$rss_file = fopen($file, "w");
		if ($rss_file) {
			$status = fwrite ($rss_file, $result);
			fclose($rss_file);
		} else {
			$status = false;
		}
	}
	return $status;
}


function rss_file_name($modname, $mod) {
	global $CFG;

	return "$CFG->dataroot/rss/$modname/$mod->id.xml";
}

//This function return all the common headers for every rss feed in the site
function rss_standard_header($title = NULL, $link = NULL, $description = NULL) {

	global $CFG, $USER;

	static $pixpath = '';

	$status = true;
	$result = "";

	if (!$site = get_site()) {
		$status = false;
	}

	if ($status) {

		//Calculate title, link and description
		if (empty($title)) {
			$title = format_string($site->fullname);
		}
		if (empty($link)) {
			$link = $CFG->wwwroot;
		}
		if (empty($description)) {
			$description = $site->summary;
		}

		//xml headers
		$result .= "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
		$result .= "<rss version=\"2.0\">\n";

		//open the channel
		$result .= rss_start_tag('channel', 1, true);

		//write channel info
		$result .= rss_full_tag('title', 2, false, strip_tags($title));
		$result .= rss_full_tag('link', 2, false, $link);
		$result .= rss_full_tag('description', 2, false, $description);
		$result .= rss_full_tag('generator', 2, false, 'Moodle');
		if (!empty($USER->lang)) {
			$result .= rss_full_tag('language', 2, false, substr($USER->lang,0,2));
		}
		$today = getdate();
		$result .= rss_full_tag('copyright', 2, false, '&#169; '. $today['year'] .' '. format_string($site->fullname));
		/*
	   if (!empty($USER->email)) {
			$result .= rss_full_tag('managingEditor', 2, false, fullname($USER));
			$result .= rss_full_tag('webMaster', 2, false, fullname($USER));
		}
	   */

		//write image info
		$rsspix = $CFG->pixpath."/i/rsssitelogo.gif";

		//write the info 
		$result .= rss_start_tag('image', 2, true);
		$result .= rss_full_tag('url', 3, false, $rsspix);
		$result .= rss_full_tag('title', 3, false, 'moodle');
		$result .= rss_full_tag('link', 3, false, $CFG->wwwroot);
		$result .= rss_full_tag('width', 3, false, '140');
		$result .= rss_full_tag('height', 3, false, '35');
		$result .= rss_end_tag('image', 2, true);
	}

	if (!$status) {
		return false;
	} else {
		return $result;
	}
}

//This function returns the rss XML code for every item passed in the array
//item->title: The title of the item
//item->author: The author of the item. Optional !!
//item->pubdate: The pubdate of the item
//item->link: The link url of the item
//item->description: The content of the item
function rss_add_items($items) {

	global $CFG;

	$result = '';

	if (!empty($items)) {
		foreach ($items as $item) {
			$result .= rss_start_tag('item',2,true);
			//Include the category if exists (some rss readers will use it to group items)
			if (isset($item->category)) {
				$result .= rss_full_tag('category',3,false,$item->category);
			}
			$result .= rss_full_tag('title',3,false,strip_tags($item->title));
			$result .= rss_full_tag('link',3,false,$item->link);
			$result .= rss_add_enclosures($item);
			$result .= rss_full_tag('pubDate',3,false,gmdate('D, d M Y H:i:s',$item->pubdate).' GMT');  # MDL-12563
			//Include the author if exists 
			if (isset($item->author)) {
				//$result .= rss_full_tag('author',3,false,$item->author);
				//We put it in the description instead because it's more important 
				//for moodle than most other feeds, and most rss software seems to ignore
				//the author field ...
				$item->description = get_string('byname','',$item->author).'. &nbsp;<p>'.$item->description.'</p>';
			}
			$result .= rss_full_tag('description',3,false,$item->description);
			$result .= rss_full_tag('guid',3,false,$item->link,array('isPermaLink' => 'true'));
			$result .= rss_end_tag('item',2,true);

		}
	} else {
		$result = false;
	}
	return $result;
}

//This function return all the common footers for every rss feed in the site
function rss_standard_footer($title = NULL, $link = NULL, $description = NULL) {

	global $CFG, $USER;

	$status = true;
	$result = '';

	//Close the chanel
	$result .= rss_end_tag('channel', 1, true);
	////Close the rss tag
	$result .= '</rss>';

	return $result;
}

//This function return an error xml file (string)
//to be sent when a rss is required (file.php)
//and something goes wrong
function rss_geterrorxmlfile() {

	global $CFG;

	$return = '';

	//XML Header
	$return = rss_standard_header();

	//XML item
	if ($return) {
		$item = new object();
		$item->title = "RSS Error";
		$item->link = $CFG->wwwroot;
		$item->pubdate = time();
		$item->description = get_string("rsserror");
		$return .= rss_add_items(array($item));
	}

	//XML Footer
	if ($return) {
		$return .= rss_standard_footer();
	}

	return $return;
}

// ===== This function are used to write XML tags =========
// [stronk7]: They are similar to the glossary export and backup generation
// but I've replicated them here because they have some minor
// diferences. Someday all they should go to a common place.

//Return the xml start tag
function rss_start_tag($tag,$level=0,$endline=false,$attributes=null) {
	if ($endline) {
	   $endchar = "\n";
	} else {
	   $endchar = "";
	}
	$attrstring = '';
	if (!empty($attributes) && is_array($attributes)) {
		foreach ($attributes as $key => $value) {
			$attrstring .= " ".$key."=\"".$value."\"";
		}
	}
	return str_repeat(" ",$level*2)."<".$tag.$attrstring.">".$endchar;
}

//Return the xml end tag
function rss_end_tag($tag,$level=0,$endline=true) {
	if ($endline) {
	   $endchar = "\n";
	} else {
	   $endchar = "";
	}
	return str_repeat(" ",$level*2)."</".$tag.">".$endchar;
}

//Return the start tag, the contents and the end tag
function rss_full_tag($tag,$level=0,$endline=true,$content,$attributes=null) {
	global $CFG;
	$st = rss_start_tag($tag,$level,$endline,$attributes);
	$co="";
	$co = preg_replace("/\r\n|\r/", "\n", htmlspecialchars($content));
	$et = rss_end_tag($tag,0,true);

	return $st.$co.$et;
}

//////////////////// LIBRARY FUNCTIONS FOR RSS_CLIENT BLOCK ////////////////

//initialize default config vars for rss_client block if needed
if (!isset($CFG->block_rss_client_submitters) ) {
	$CFG->block_rss_client_submitters = 1; //default to admin only
}
if (empty($CFG->block_rss_client_num_entries) ) {
	$CFG->block_rss_client_num_entries = 5; //default to 5 entries per block
}
if (!isset($CFG->block_rss_client_timeout) ) {
	$CFG->block_rss_client_timeout = 30; //default to 30 mins
}

// Defines for moodle's use of magpierss classes
define('MAGPIE_DIR', $CFG->libdir.'/magpie/');
define('MAGPIE_CACHE_DIR', $CFG->dataroot .'/cache/rsscache');
define('MAGPIE_CACHE_ON', true); //might want to expose as an admin config option, but perhaps this is something that should truly just be on unless the code is tweaked
define('MAGPIE_CACHE_FRESH_ONLY', false); //should be exposed as an admin config option
define('MAGPIE_CACHE_AGE', $CFG->block_rss_client_timeout * 60);
define('MAGPIE_DEBUG', $CFG->debug); // magpie, like moodle, takes an integer debug

// defines for config var block_rss_client_submitters
define('SUBMITTERS_ALL_ACCOUNT_HOLDERS', 0);
define('SUBMITTERS_ADMIN_ONLY', 1);
define('SUBMITTERS_ADMIN_AND_TEACHER', 2);

/**
 * @param int $courseid The id of the course the user is currently viewing
 * @param int $userid We need this to know which feeds the user is allowed to manage
 * @param int $rssid If present the rss entry matching this id alone will be displayed
 *			as long as the user is allowed to manage this feed
 * @param object $context we need the context object to check what the user is allowed to do.
 */
function rss_display_feeds($courseid, $userid, $rssid='', $context) {
	global $db, $USER, $CFG;
	global $blogid; //hackish, but if there is a blogid it would be good to preserve it

	require_once($CFG->libdir.'/tablelib.php');

	$select = '';
	$managesharedfeeds = has_capability('block/rss_client:manageanyfeeds', $context);
	$manageownfeeds = has_capability('block/rss_client:manageownfeeds', $context);

	if ($rssid != '') {
		$select = 'id = '.$rssid.' AND ';
	}
	if ($managesharedfeeds) {
		$select .= '(userid = '.$userid.' OR shared = 1)';
	} else if ($manageownfeeds) {
		$select .= 'userid = '.$userid;
	}

	$table = new flexible_table('rss-display-feeds');

	$table->define_columns(array('feed', 'actions'));
	$table->define_headers(array(get_string('feed', 'block_rss_client'), get_string('actions', 'moodle')));

	$table->set_attribute('cellspacing', '0');
	$table->set_attribute('id', 'rssfeeds');
	$table->set_attribute('class', 'generaltable generalbox');
	$table->column_class('feed', 'feed');
	$table->column_class('actions', 'actions');

	$table->setup();

	$feeds = get_records_select('block_rss_client', $select, sql_order_by_text('title'));

	if(!empty($feeds)) {
		foreach($feeds as $feed) {

			if (!empty($feed->preferredtitle)) {
				$feedtitle = stripslashes_safe($feed->preferredtitle);
			} else {
				$feedtitle =  stripslashes_safe($feed->title);
			}

			if ( ($feed->userid == $USER->id && $manageownfeeds)
					|| ($feed->shared && $managesharedfeeds) ) {

				$feedicons = '<a href="'. $CFG->wwwroot .'/blocks/rss_client/block_rss_client_action.php?id='. $courseid .'&amp;act=rssedit&amp;rssid='. $feed->id .'&amp;shared='.$feed->shared.'&amp;blogid='. $blogid .'">'.
							 '<img src="'. $CFG->pixpath .'/t/edit.gif" alt="'. get_string('edit').'" title="'. get_string('edit') .'" /></a>&nbsp;'.

							 '<a href="'. $CFG->wwwroot .'/blocks/rss_client/block_rss_client_action.php?id='. $courseid .'&amp;act=delfeed&amp;rssid='. $feed->id.'&amp;shared='.$feed->shared.'blogid='. $blogid .'" 
				onclick="return confirm(\''. get_string('deletefeedconfirm', 'block_rss_client') .'\');">'.
							 '<img src="'. $CFG->pixpath .'/t/delete.gif" alt="'. get_string('delete').'" title="'. get_string('delete') .'" /></a>';
			}
			else {
				$feedicons = '';
			}

			$feedinfo = '
	<div class="title">
		<a href="'. $CFG->wwwroot .'/blocks/rss_client/block_rss_client_action.php?id='. $courseid .'&amp;act=view&amp;rssid='.$feed->id .'&amp;blogid='. $blogid .'">
		'. $feedtitle .'</a>
	</div>
	<div class="url">
		<a href="'. $feed->url .'">'. $feed->url .'</a>
	</div>
	<div class="description">'.$feed->description.'</div>';

			$table->add_data(array($feedinfo, $feedicons));
		}
	}

	$table->print_html();
}


/**
 * Wrapper function for rss_get_form
 */
function rss_print_form($act='none', $url='', $rssid='', $preferredtitle='', $shared=0, $courseid='', $context) {
	print rss_get_form($act, $url, $rssid, $preferredtitle, $shared, $courseid, $context);
}


/**
 * Prints or returns a form for managing rss feed entries.
 * @param string $act The current action. If "rssedit" then and "update" button is used, otherwise "add" is used.
 * @param string $url The url of the feed that is being updated or NULL
 * @param int $rssid The dataabse id of the feed that is being updated or NULL
 * @param string $preferredtitle The preferred title to display for this feed
 * @param int $shared Whether this feed is to be shared or not
 * @param int $courseid The id of the course that is currently being viewed if applicable
 * @param object $context The context that we will use to check for permissions
 * @return string Either the form is printed directly and nothing is returned or the form is returned as a string
 */
function rss_get_form($act='none', $url='', $rssid='', $preferredtitle='', $shared=0, $courseid='', $context) {
	global $USER, $CFG, $_SERVER, $blockid, $blockaction;
	global $blogid; //hackish, but if there is a blogid it would be good to preserve it
	$stredit = get_string('edit');
	$stradd = get_string('add');
	$strupdatefeed = get_string('updatefeed', 'block_rss_client');
	$straddfeed = get_string('addfeed', 'block_rss_client');

	$returnstring = '';

	$returnstring .= '<form action="'. $CFG->wwwroot .'/blocks/rss_client/block_rss_client_action.php" method="post" id="block_rss">'."\n";
	print_location_comment(__FILE__,__LINE__);
	$returnstring .= '<div id="rss_table">'."\n";
	if ($act == 'rssedit') {
		$returnstring .= $strupdatefeed;
	} else {
		$returnstring .= $straddfeed;
	}

	$returnstring .= "\n".'<br /><input type="text" size="60" maxlength="256" name="url" value="';
	if ($act == 'rssedit') {
		$returnstring .= $url;
	}

	$returnstring .= '" />'."\n";
	$returnstring .= '<br />'. get_string('customtitlelabel', 'block_rss_client');
	$returnstring .= '<br /><input type="text" size="60" maxlength="128" name="preferredtitle" value="';

	if ($act == 'rssedit') {
		$returnstring .= $preferredtitle;
	}

	$returnstring .= '" />'."\n";

	if (has_capability('block/rss_client:createsharedfeeds', $context)) {
		$returnstring .= '<br /><input type="checkbox" name="shared" value="1" ';
		if ($shared) {
			$returnstring .= 'checked="checked" ';
		}
		$returnstring .= '/> ';
		$returnstring .= get_string('sharedfeed', 'block_rss_client');
		$returnstring .= '<br />'."\n";
	}

	$returnstring .= '<input type="hidden" name="act" value="';

	if ($act == 'rssedit') {
		$returnstring .= 'updfeed';
	} else {
		$returnstring .= 'addfeed';
	}

	$returnstring .= '" />'."\n";
	if ($act == 'rssedit') {
		$returnstring .= '<input type="hidden" name="rssid" value="'. $rssid .'" />'. "\n";
	}

	$returnstring .= '<input type="hidden" name="id" value="'. $courseid .'" />'."\n";
	$returnstring .= '<input type="hidden" name="blogid" value="'. $blogid .'" />'."\n";
	$returnstring .= '<input type="hidden" name="user" value="'. $USER->id .'" />'."\n";
	$returnstring .= '<br /><input type="submit" value="';
	$validatestring = "<a href=\"#\" onclick=\"window.open('http://feedvalidator.org/check.cgi?url='+getElementById('block_rss').elements['url'].value,'validate','width=640,height=480,scrollbars=yes,status=yes,resizable=yes');return true;\">". get_string('validatefeed', 'block_rss_client')."</a>";

	if ($act == 'rssedit') {
		$returnstring .= $stredit;
	} else {
		$returnstring .= $stradd;
	}

	$returnstring .= '" />&nbsp;'. $validatestring ."\n";
	// $returnstring .= '</div></form>'."\n"; // Avoiding nested forms... Ugly temporary hack #8922
	return $returnstring . print_location_comment(__FILE__, __LINE__, true);
}


/**
* Adds RSS Media Enclosures for "podcasting" by examining links to media files,
* and attachments which are media files. Please note that the RSS that is
* produced cannot be strictly valid for the linked files, since we do not know
* the files' sizes and cannot include them in the "length" attribute. At
* present, the validity (and therefore the podcast working in most software)
* can only be ensured for attachments, and not for links.
* Note also that iTunes does some things very badly - one thing it does is
* refuse to download ANY of your files if you're using "file.php?file=blah"
* and can't use the more elegant "file.php/blah" slasharguments setting. It
* stops after ".php" and assumes the files are not media files, despite what
* is specified in the "type" attribute. Dodgy coding all round!
*
* @param	$item	 object representing an RSS item
* @return   string	RSS enclosure tags
* @author   Hannes Gassert <hannes@mediagonal.ch>
* @author   Dan Stowell
*/
function rss_add_enclosures($item){

	global $CFG;

	$returnstring = '';
	$rss_text = $item->description;

	// list of media file extensions and their respective mime types
	include_once($CFG->libdir.'/filelib.php');
	$mediafiletypes = get_mimetypes_array();

	// regular expression (hopefully) matching all links to media files
	$medialinkpattern = '@href\s*=\s*(\'|")(\S+(' . implode('|', array_keys($mediafiletypes)) . '))\1@Usie';

	// take into account attachments (e.g. from forum) - with these, we are able to know the file size
	if (isset($item->attachments) && is_array($item->attachments)) {
		foreach ($item->attachments as $attachment){
			$extension = strtolower(substr($attachment->url, strrpos($attachment->url, '.')+1));
			if (isset($mediafiletypes[$extension]['type'])) {
				$type = $mediafiletypes[$extension]['type'];
			} else {
				$type = 'document/unknown';
			}
			$returnstring .= "\n<enclosure url=\"$attachment->url\" length=\"$attachment->length\" type=\"$type\" />\n";
		}
	}

	if (!preg_match_all($medialinkpattern, $rss_text, $matches)){
		return $returnstring;
	}

	// loop over matches of regular expression
	for ($i = 0; $i < count($matches[2]); $i++){
		$url = htmlspecialchars($matches[2][$i]);
		$extension = strtolower($matches[3][$i]);
		if (isset($mediafiletypes[$extension]['type'])) {
			$type = $mediafiletypes[$extension]['type'];
		} else {
			$type = 'document/unknown';
		}

		// the rss_*_tag functions can't deal with methods, unfortunately
		$returnstring .= "\n<enclosure url='$url' type='$type' />\n";
	}

	return $returnstring;
}
?>
